Nonacid photogeaphic oxidizers



Patented Feb. 9, 1954 f'No'Drawing. ApplicationApr-il 11; 1949,

' "Serial No..86,867

3 Claims.

Thisinvention relates to non-acid, photographic oxidizer-modifiers used for adjusting the v.imageuclarity and intensity, in whole. or. in, part,

including retouching, on the various types of .t photographic negatives slides,:. and other transparencies; as well i as on the many types of :photographic prints. The invention: includes also. new

' and transparent" resists for i dint: use 'with these oxidizers 1 and others-lay being :applied on the emulsion surfaceover those'parts of it orzof the image that arenot tos-be'aeted' on by'theoxidizer. The various non-acid oxidizer-modifiers of the Y invention are effective for clarifying; for example, by. removing the'hazeorveil thatgives a trans :parency-ia flat-or"blurred:..appearance, independ- ".ently*of,1- and 'especially if, it was overexposed-z or .woverdevelope'd;and'iorretouching,photographic negatives, prints, ".and ipictures of various types,

.itfor example,s. 'blackr.and.white,"'negatives as *Well iaszrpositives, i such '1 as 'Xerayplates, emotion" picture films, and especially color separation-;pic-

.tures and color transparencies, produced for example; -by..additive. color. photographic processes, such as motion picture negatives, lantern slides -and the like, as well as to adjust the tint of the yellow'component of the subtractive color process.

This application is a continuation-in-part of .,my-copending application Serial No; 642,981; filed Januaryr23, 1946,; andrrnow"v Eatent N 0.1:: 2,467.;357, issued April 12, 1949, whichinturn:iszatcontinuation of my application Serial No. 453,671 (abandoned subsequent to the 'flling of my application Serial" 642,981) "filed-"August 5, 1942," and which I in turnis-a continuation-in-part of my application Serial No. 352,517, filedAugust 14, 1940, and abandoned subsequent to the filing of'my application Serial No. 453,671.

Fundamentally the non-acid oxidizer-modifiers of the invention manifest their. effectiveness for their various respective applications 'by' containing at least one halogen accompanied by at least aqueous, acid aqueous, aqueous alcohol,-andacid aqueous alcohol media. Among them the aider'hydes'areespecially useful andof th'ese'formalderhyde iis generally "particularlyi distinctively 'efiective'.

The-individual halogens show individual behaviordependent" on' the'particularvariations. :of compositions and conditions employed. "Iodine long and substantially .unlimite'd periods the halogen, e g. iodine,pcont,ent,.-tas,-,exempl r by taking ahi'gh concentration (up to; saturation) of crystallineiodine into water solutionibyusing and bromine for the. mostpart. areadistinctivialy effective and .of these iodineis moreagenerally desired because of the. more ,general.- .e1nployment of the iodide of. silversini photosensitive :films. Chlorine and. fluorine manifestcertain;similarities in behavior and of the twochlorine;.may ..be the more iavoredin use becausenf-the more general commercial use of. chlorine oiflthettwo of them.

The halogen and the-aldehyde ordzetone are .used'together as the. principal ingredientsnftmy non-acid oxidizer-modifiers most generally, iman essentially aqueous vehicles In thecaseof iodine, it is advantageousand preferable,..-to efEectLthe dissolution of the iodine insuch vehicle,i to.;;use an alkali metal salt. capable. of taking iodine. into aqueous solution, for example ..,an',;.alkali. metal iodide such as potassiumiodide oranalk'ali metal thiosulphate ,as sodiumthiosulphate. Moreover. when I use a highly. concentratedtandgadvantageously saturated solutionof iodine...in.-alkali metal iodide-containing water, I. .can replace the aldehyde or ketone' by one of'theqdec'olorized iodine solutions which usually. containiodine..,dis-.

solved in water by the aidof anflalkalimtal iodide orthiosulfate withlthe additionofta'iilittle alcohol and'decolorized bythe inclusion ofiam- "monia andcdiluted and stabilized.with-moreaicohol, such as the." tincture dec'olorizediodine, Idesignated in the examples. as decolorized iodine N. IVand included in "The National Formulary, third and fourtheeditions published" by J. B. Lippincott Company,"Philadelphia,.l?ennsylvania, United States of America; and mothers of the examples as fdecolorized. iodine NI'TF. VI," for the modification given inrthe' fifth through eighth editions of the same publication.

' intensity, in whole or in part, and including removal of the veil or haze, retouching;;control"or contrast and also of softness; and also clarifying -half tone dot etchingscreen"bearing-images;

batch of non-acid oxidizer-modifier ..ordinari1y will keep 'usually;.ior; about. ,a .working..ida'ys period, generally 'fromseveral." hourshsay ssix or seven, tOItWOOI" three days-or more.;depending on' the individual composition. Although my non-acid oxidizer-modifiers are stable for very preferably an aqueous potassium iodide'solution 1 water (37%).

until bubbles of gas no longer escape, and the as solvent for the iodine, and then adding the aldehyde or ketone, such as formaldehyde.

In many of the illustrative examples there are included particular amounts of certain specifically individually designated iodine solutions, the detailed constitution and preparation of which follows:,

(alConcentrated iodine.This is actually a saturated aqueous solution of iodine prepared, for example, by dissolving one ounce of crystalline potassium iodide in three liquid ounces of water and then adding more and more crystalline iodine until the solution is seen to be saturated with iodine as noted by the failure of any more of it to go into solution. After filtering off the excess or undissolved iodine, the concentrated (thus saturated) iodine solution is ready for use as an ingredient in the various oxidizer-modifier compositions.

' (b) Decolorized iodine N. F. VI is prepared by addition to a solution of 25 grams of potassium iodide in 400 cc. of water of 50 grams of iodine and 400 cc. of alcohol and stirring. After the iodine is completely dissolved, 100 cc. of stronger ammonia water (about 37% NI-Is) are added and Thereafter suflicient alcohol is added Decolorizediodine N. F. IV.Digest 83 grams each of iodine and sodium thiosulphate in 100 cc. of water, at a gentle heat, until complete solution results. Then add 125 cc. of alcohol and afterwards 65 cc. of stronger ammonia Shake the mixture a few minutes liquid has become colorless with a white precipitate suspended in it. Now cool the mixture, and then add sufficient alcohol to make the product measure 1000 cc. Place the bottle containing the liquid in a cold place for a few hours and then filter. Preserve in a well-stoppered bottle.

(d) Tincture of iodine U. S. P.-Dissolve "I0 grams of potassium iodide in 50 cc. of distilled water contained in a bottle graduated to 1000 00.;

add 70 grams of iodine and agitate the mixture until solution is effected. Then add suflicient alcohol to make 1000 cc., and mix thoroughly.

4 (2) Concentrated iodine solution drams 1 Decolorized iodine N. F. VI do 3 Formalin dn 3 Distilled water liq. oz 16 This oxidizer solution, most advantageously effective for clarifying extremely dense color transparencies where no white objects are visible, is preferably made by diluting the concentrated iodine with half of the water, separately combining the decolorized iodine and the formalin, and thereafter combining the two solutions. Then the second half of the water is added and the oxidizer is ready for use without filtering.

(3) For the present, I prefer the following oxidizer for clarifying detail in color transparencies:

Tincture of iodine U. S. P drams 3 Decolorized tincture of iodine N. F. VI

drams.-- 3 Formalin do 1-3 Distilled water liq. oz 16 This oxidizer is prepared, for example by placing the acid in a bottle and slowly, and cautiously where necessary, pouring into it half of the water, then combining this acid solution with the tincture of iodine, the decolorized iodine and the formalin, and thereafter adding the second half of the water. No filtering is necessary.

If it is desired to use this oxidizer-modifier on paper prints, two ounces of common salt or sugar should be added. This oxidizer is prepared, for example, by adding half of the water to the tincture of iodine, then the decolorized iodine and the formalin, and thereafter adding the second half of the water. No filtering is necessary.

(4) The following oxidizer-modifier can also be used for adjusting the clarity of color transparencies:

Tincture of iodine U. S. P drams 3 Decolorized tincture of iodine N. F. VI

. drams 3 Formalin do 1 to 3 Distilled water liq. oz '7 17 grams of iodine and not less than 3 grams and not morethan 4 grams of potassium iodide in each 100 cc.

(g) Lugols solution iodine compound is the standard U..S..Pharmacopoeia solution containing in each 100 cc. not less than 4.5 grams and not more than 5.5 grams of iodine and not less than 9.5 grams and not more than 10.5 grams of potassium iodide.

My non-acid oxidizer-modifiers are illustrated v by, but not restricted to, the following examples:

(1) Concentrated iodine drams 1 Decolorized iodine N. F. VI do 3 Formalin (40% I-ICHO) d0 1 Distilled water liq. oz 16 This oxidizer presently most effective for substantially all of the above mentioned applications is prepared preferably by combining the concentrated iodine and the decolorized iodine, and then adding half of the water, the formalin. and I then adding the rest of the distilled water,

I prefer to make this solution by first combining the iodine with the formalin and then adding the water, and filtering.

(5) Tincture of iodine U. S. P drams 3 Decolorized tincture of iodine N. F. IV

drams 3 Formalin do 1 to 3 Distilled water liq. oz 7 This oxidizer-modifier is prepared substantially similarly to that of example 4. Use of decolorized tincture of iodine N. F. IV makes the filtering step of Example 4 unnecessary.

(6) The following is a presently preferred oxidizer-modifler that is well adapted for developing softness on color transparencies and on prints:

Iodine test solution U. S. P drams 2 or 3 Potassium iodide test solution U, S. P.

drams 1 Distilled water oz 7 ('7) Another oxidizer that also works well is the following:

assesses Prepare this-:oxidizzer xbyifirstodilutingithedodine testisolutionrwithtrhalfiiofrflzheizwatercandiin::se-s quence addrthe'zdecolorized iodine athe; potassium iodine test solutionrtthe:etincturezofwiodine;and the formalinaandrfinally \thex rest-.- of; the water. Thissolution works .veryiwells but withimabout 6 to 1-0: days becomesudecolorized -andarpraotically ineffective-1 4:Bf iadditionof suflieient ot-avstnong iodine'cssolutiomfomexample, tincture f iodine oraconcentratedriodineiiti is'revivedz-to its former strengthii (disclosing iodine compound (Lugoll strongerithanwany: of those in the preceding examples.-andiespecially adaptede for-half-tonedot etching'isipreparedbytaking any of the oxidizermodifierssolutions- :of any, ofr .the precedingex! l amples, in the amount -.of. 8 oz. and-adding the following Ounces Tinctureuofiiodine U.-S-.,P-. About 2 /2 Formal-in About 2 Iri' pla'ceof tincture of iodineg'l to- PA; 0210f con centrated iodine-can" be I used just-as well;- In all cases th'e quantities are in liquid measure;

While formaldehyde is included as the illusmauvealdehydeon 1 each of' *the preceding: examples,- it -is'unde'rstood that other suit'abl'e aldehyds 'can replace it equivalent" amounts; as exemplifiedby-'- the following example:

(H)- Concentratediiodine; drams; 3

.Acetaldehyde d0. 1 120 3 Distilled-water -liq; oz' .8 to '16 The concentrated iodine can be: replaced by'fi drains of tincture ofliiodiiie UL'S. P; or of any of the. dilute iodine solutionsosuchoas anytofwthe iodine test solutions, dec'olorizediodines, Churchills' tincture, or'Lugols tincture, and the like .A corresponding solution "can be prepared with" the equivalent amountofany othenavailable efiecti'v'e aldehyde? such as furfural'dehyde, and; .the

like: The oxidizer-modifiers made with alde-t h ydes' other than formaldehyde-= show activity relativelyeomparablewith it "in the variou uses, but aresomewhatunder it as to" duration iii' -keep ingxt'qualities; .ThePnon-acid: oxidizer-modifiers havingracetaldehyderon afurfuraldehyde are com arablyqas :efieoti've :asithe (formaldehyde containtion)? li'q. oz: 4 Form'alin drams 4 Waterto make a total'of' lid. 02;." 8'

This compositiomcam be'use'dofor adjusting: the yeli'oiwtcolnrz componentrzof 'an: image developed'on Kodachrome: fiim'; although. on suchgfilms it. preferable citoriuse z: azitweak'r solution;.-:;such p as: 1; one. that isiialready:partlyxexhausted;- This: oxidizer composed with chlorine, or =in":*-its:place:aa 'similar quantitygcofi: fluorinaaeinsothei same. concentration aqueouszzsolutioneshows:zits effectiveness :usually by; attacking more: strongly the silver in: 1 the darkerzparts athesiimage thana-do the-composh tions containingiiodine: An examplewith fluorine (I4)"F1uorine- (-as '3t aqueous solution) "lid." 02;. 3 Formalin drams 3to 4 Distilledwater -1i'q;-'oz 6130-8 Other-H desirable illustrative-l but not limiting,- examplesaxof T the anon-acid: species .-:0f oxidizermodifiers-Jane:

(15) Concentratedviodinee drams 3 Formali'ne do 7 3 Waterr -.l-iq. ozen. 10.120 12 Thisoxidizen; prepared by combining the iodine solution andv water, and 1. adding, the formalin, brings. out. strikingly well the contrasts in ya picturevbyit'smefiecting more .ofeth'e lighter. partsiof the picture-than the darkerones. M

An oxidizer "that makes a softer "pictureebyits efiecting. .the darker parts. of it Lr'ath'er than; the greyoparts.offtherimage, isillustratediby the following:

(16) Concentrated?iodine. dram-s 2 to 3 "Decolorized iodine NMF. IV or' Water -.liq. oz 10170 12 Th'isis preparedbymixing'the water and'the con centrated iodine" and '"adding' the deoolorized iodine and' 'shaking-welli Theinclusion" of the de+ oolorized iodine-appears to" operate to retard'th'e characteristic" 'fat 'lik'e"- spreading" appearance ordinarily shown by concentrated iodine alone and' thereby balances the oxidizer and: makes" it especially-"eifective for"paper*prints.

Theiodineinthislastexample can'be replaced by equivalent-amountsrespectively of chlorine, brominemr" fluorine; each-'separatelyiin' aqueous solution" ofithfthe 'str'engtirshown," for example; in- Examples 12' and 13 respectively and .with similar"effectiveness:

While all ofthe preceding -examples'show some aldehydfas' "arparticular"constituent of my oxi-' dizer 'modifiera'forfunctioning'in' them';;I believe, insome mannerto" contfol'or restrain the activ ity oiiltlie""halogenonqthe.v liberated silver in'the image and""thereby javoidiany. v destruction of the details ,Of."it, Imay use instead a ketone of the typeh'ereinabove described}; fol: example, in. acomposition of z (I7 3' Tincture otiodine .SeP, drams .n 3

Suchcompositions:containingiarketoneishow good 7 effectiveness invarious oi the indicated photographic applications.

Except when they are prepared from one of the concentrated iodine solutions, such as a saturated iodine solution or tincture of iodine U. S. P., the non-acid oxidizer-modifiers keep for only a short time, as noted above for from several hours to for the best part possibly two or three days, or perhaps slightly longer, depending on composition and conditions. It is usually undesirable to use my oxidizer-modifiers in clear daylight when adjusting photo images as they lose activity to a measure in such light.

The water constituent has been included as distilled Water in the various preceding examples because it is most dependable. However, the recently made available demineralized water is adequately useful as well as any good quality tap water. Actually, the primary precaution is that the water should not have excessive silica. and lime content.

The capacity of my non-acid oxidizer-modifiers for correcting the transparenc of an entire picture is of considerable importance in color transparencies. It is well known that even with the most carefully exposed and processed color transparencies made by additive color processes, and just as occurs in ordinary black and white, or even in color separation, negatives and prints, there is formed a haze or veil that give the transparency a more or less fiat and blurred appearance, independently of whether, and especially if, it was slightly under or over-exposed, thereby preventing the transparencies from appear ing to the observer in the natural colors. My oxidizer-modifiers eliminate this haze or veil, and equally as well from black and white transparencies and prints.

Generally a color transparency is kept in the oxidizer bath from about 1 to 5 minutes, depending on the density of the transparency. In the oxidizer bath, a gre tinge forms over the transparency, but disappears after the usual hypo treatment. The action is somewhat different on glossy and on mat papers. Glossy paper prints remain absolutely clear during rocessing while mat paper prints become covered overall with a green-grey and violet veil which disappears in the hypo treatment. The normal time of treatment is about 1 to 3 minutes, depending on the characteristics of the light sensitive paper used and the density of the printed picture. For prints, it is preferable to use one of the concentrated iodine containing non-acid type such as those of Examples 13, 14 and 15. This concentrated non-acid type keeps indefinitely.

My non-acid oxidizer-modifiers are also used for retouching small parts of pictures, such as for removing or lightening dark spots, such as blemishes, freckles, wrinkles and the like, for example, on black and white and color separation pictures or on color transparencies not quite completely satisfactory results are obtained if for such local retouching there is used an of my solutions of the various preceding examples as these work too slowly for this purpose. I therefore prefer to use for this purpose a strong oxidizer solution, which can be designated as a local oxidizer-modifier, illustrated by:

Drams (18) Tincture of iodine U.S.P. (alcohol 83%) 3 Decolorized tincture of iodine N. F. IV 3 Formalin 3 Glycerine (to be added before using, preferably to a medium syrupy viscosity).

8 I The tincture of iodine can be replaced b onehalf dram of concentrated iodine. The other ingredients have to be dissolved in the glycerine before using this oxidizer-modifier. As above composed it will keep indefinitely without addition of glycerine, but addition of glycerine greatly increases its life, even when kept in an open vessel ready for use. This oxidizer is highly active and should be applied very gently for otherwise it may burn holes in the image being treated. It is unnecessary to rub with the brush while applying this oxidizer for each dab gives almost instantly a retouching result. Immediately after noting that the applied local oxidizer obtained the desired result, thespot to which it was applied should be treated with a strong hypo. It is important to avoid touching other places with the hypo. After applying the hypo, the retouched film or color transparency has to be washed thoroughly. When larger areas areto be treated with this oxidizer for retouching purposes, it is advisable first to cover such area with a glycerine and water solution (medium syrupy viscosity) and thereafter to do the retouching within that area. The function of the glycerine here and in the oxidizer is to protect the edges of the film, and especially of the paper print (due to the greater absorbability of the paper), and also in local retouching to avoid leaving a sharp outline about the retouched area, due to the high activity of such stronger oxidizermodifier.

My non-acid oxidizer-modifiers are specially adapted for treating photographic prints where it is necessary to adjust their contrast or softness. In removing the haze or veil from an image, my oxidizer-modifiers in essence serve as a photographic reducer (not to be confused with the same word in its strict chemical parlance).

My non-acid oxidizer-modifiers in general are easily prepared for use, inexpensive, and efiectively adapted for the various purposes enumerated above. Their use on transparencies bearing also an image of a half-tone dot etching screen,

- as more fully discussed hereinbelow, greatly simplifies that process, makes it easier to control and yields much better results than by other known methods.

My non-acid oxidizer-modifiers can be used. also for a novel method of local color correction by oxidation. This includes the steps of coating with my new and transparent resists the picture portions of the emulsion, which are not to be corrected, immersing the emulsion in one of my oxidizer baths for a sumcient time for the correcting action on the uncoated parts of the picture, and, after bathing the picture in a special hypo described below, removing the resist from the emulsion. The parts not to be treated with the oxidizer can be coated with my new resists either in the usual manner or by application with an air brush. By the usual method, there occurs a sharp outline between the treated and untreated image portions, while with an air brush a soft merging edge portion between these image parts is obtained. Thus, it is possible to correct picture parts of color transparencies, even also, if desired, to make one or the other color lighter or brighter.

By this process I can correct also one or the other partof any one of the color separation negatives, and thereby correct the final color transparency obtained after combining them. The oxidizer-modifiers made with decolorized with. my: new. resistsmyhich are,- compositionsof matter comprising a transparentysubfi ienfifiinert to gelatin and selected from the grou consist ng of transparent waxy and resinous substances a d dissolvedgin-a. transparent, liquid; solvent ipnsaid substances and vrhicnis; inerttmand-nota sol venttor, gelatin; for-example,- preferably Canada balsam as the solutesand benzol the solvent. They can be produced eitherin arquickedryingbr in: anon-drying. type.

If theresist is to .be. applied rip; the vusual...way, then I prepare it by dissolving one part by .volume of :Canada': balsam in. aboutra. partseby volume of .benzol or othersolventafor the. Canada.=.balsam. -If :it is :to :be;applied.:with an airbrush-,- then it is advisable to use. a solutioncomprising oneipart by volume Canada balsam dissolyed-ineabout liinto id-parts of benzol by volume.

@My non-drying transparent --resist|.advantageouslycomprises beeswax, lanolin,- and white petrolatum, a preferred composition-for it-cnsisting :of Grams .-Bee wax. .whit .c ye low. prefer bly white 1 Lanolin wool fat) 2 -.,White petrolatumfl Between 12 and 15 Inzthis .type nosolvent isused. Other. suitable examples are .anwtwooithe foregoing three ingredients combined together.

I caminclude certain additional ingredientsto make-anon-drying,opaque'resist-if desired. For

this, I include in the above described non drying transparent -resist-compositions;Indian red pi ment or white lead carbonate or other compatible substances.

As a drying, opaque resist, the following composition can be used (by weight) Ounces Beeswax 4 Oil of turpentine 3 Asphalt varnish (e. g. Eimer and Amend make) 1 Red pigment About 14 White lead carbonate About 1 This opaque resist cannot be washed off with cold water, but hot water will remove it.

These resists are used for the most diverse pur poses. One of the principal purposes is, as already illustrated, to cover a part of a picture during retouching and thereby withhold action of the oxidizer on such part while the uncovered other parts are processed with the oxidizer in any desired way. My new resists are especially adapted for such process for their transparency makes it possible during processing to compare the parts to be treated with those remaining untreated and thereby to regulate the time of treatment as necessary.

Another use of my resists is in the covering of a part of a picture while the adjacent part is removed. Still another field of use for my nondrying, transparent resist is to cover with them parts of pictures or paintings, retouched with an air brush. If my transparent, quick-drying resist is used, a layer of it preserves the paint from being rubbed or washed off and enhances considerably the brilliancy of the picture; and in addition preserves the paintings from cracking or discoloration. My new quick-drying resists may also be used for plates or films for natural color transparencies. In this case an extremely t inl rsreotsuic eernnsl anspare t r atta tolbeapplie t thcmlc scre l gl1t sensitiveemulsion. m in bes lq Q een is??? r nspar n -E o ts pac t tmxcneaua .quickedrrins-resists av ubs ant e l t lsems prcpertieslotmvtre esisi as described above.

M nonedtvinatr ns arc tass st ar -iner to acidsandremainine nonr in ,co timwhil thephot sra bic fi mo platen bei ,P TQCQS L thu expedi in c h .whqle. pro es s. resist ca ibeeasily and quic l pp e a als ea il and. ,comple elylremcv d f e th l o p a as been. d ied. ndthe res sti o longer n e e nQn-dry na transpare re t can b u e similarly ls onprints- Mywccpendinsapn c tio v serial .N 642.98 e c e an c ai m acid. pe es .o oxid zer: modifiers. ;By dere10.n this acid speci fou d th t; I ca orti y xi i r-modifi sothat. .ityvi l-i other ise ge ral y s a leand storable ior;asubstantially vunlimited time,- and in addition enhance. its activity in adjusting image clarity and intensity and .in retouching. I accomplished thisby including in the halogenaldehyde composition a, ,suitable quantity ofv an acid,,-,distirlctively effectively a mineral acid of the type of hydrochloric,sulphuric, sulphurous, nitrosylsulphuric,v nitric, and phosphoric acids, or

phatic, and preferably lower aliphatic and of\ necessity soluble in water or water containing possibly up to about 5 to 10% or so of alcohol, for example, formic, acetic, lactic acid, and the like. I designate the oxidizer-modifier containing an acid as an acid oxidizer-modifier.

Moreover, in situations where a strong oxidizer is needed in local retouching use, it is advantageous to dissolve the halogen, for example iodine, and the aldehyde such as formaldehyde, along with the selected acid in glycerine or other hygroscopic polyhydric alcohol. The effect of such hygroscopic substance as the vehicle for solution of the usual ingredients of my acid oxidizermodifiers is to safeguard the edges of the film and especially of the paper print due to the greater absorbability of the paper, and also in local retouching to avoid leaving a sharp outline about the retouched area, against any overactivity of such stronger oxidizer composition.

My acid oxidizer-modifiers are exemplified by adding to the composition of each of the above Examples 1 through 12, 17 and i8 hydrochloric acid 37% strength (or sulphuric acid 96-98% strength or nitric acid 70% strength) to the extent of 1 dram in each of Examples 1, 4, 5, 6, 7, 9 and 18, 2 drams in Examples 2, 3, 8 and 17, about two and one-half liquid ounces in Example 10, 1 to 2 drams in Example 11 and 2 to 4 drams in Exam le 12.

I can also influence the softness or the contrast in retouching images with either my nonacid or acid oxidizer-modifiers by including varying amounts of either sugar or common salt (NaCl) or of both as additional ingredients. This is exemplified by adding 2 ounces (by weight) of sugar or salt to the acidified compositions of Examples 1 and 2 as just above described and 1 11 ounce in Example 9. In these'examples, I find it advantageous to add the acid to half of the water, then to add the combined iodine constituents, then the salt or sugar and to shake to whichever of the latter that is added is dissolved and then to add the balance of the water. Moreover, when nitric acid is used no sugar is added.

While in each of the preceding examples hydrochloric acid (and alternately sulphuric acid or nitric acid) was included as the acid constituent of the acid oxidizer-modifiers (respectively of the same strengths as shown in Example 1) with the caution not to use nitric acid in any formula that includes salt (and vice versa), any of the other acids compatible with the other constituents of the modifier-oxidizer and the film or print to be treated, can be used in equivalent amounts, such as any acid of the type described above. Those including hydrobromic, periodic, perchloric or sulphurous acid do not have quite the extent of life as do the preparations containing any of the other acids. As already indicated, ordinarily the acid constituent in my acid oxidizer-modifier serves to increase the rate of activity of the agent.

In addition to their utility in the various kinds of photography retouching operations described in the prior portions of this specification, my acid species of oxidizer-modifiers play an important role in the formation of several surprisingly useful types of transmitted-light-modifying screens that provide certain unusually eflective optical phenomena. My non-acid oxidizer-modifiers are not suitable for making these screens. For use in making screens, it is preferable that distilled water be used in the acid-aldehyde agent.

While the invention has been illustrated by 12 describing certain specific embodiments of it, it is understood that suitable substitution of equivalents, modifications and variations may be made in them without departing from the spirit of the invention, the scope of which is recited in the appending claims.

I claim:

1. A non-acid, photographic oxidizer-modifier for adjusting the clarity of, and retouching, developed photographs, negative as well as positive, which comprises an aqueous solution of concentrated iodine, decolorized iodine, and a lower aliphatic water-soluble aldehyde.

2. A non-acid, photographic oxidizer-modifier as claimed in claim 1, wherein the aldehyde is formaldehyde.

3. A non-acid, photographic oxidizer-modifier as claimed in claim 1, wherein the concentrated iodine, decolorized iodine, and aldehyde are present respectively in amounts equivalent to about tincture of iodine U. S. P. 3 drams, about 3 drams decolorized tincture of iodine N. F. VI, and from about 1 to about 3 drams of formalin, and which oxidizer-modifier also contains about 16 liquid ounces of water.

LEON RUBINSTEIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,275,162 Falk Aug. 6, 191a FOREIGN PATENTS Number Country Date 13,088 Great Britain Oct. 26, 1911 of 1911 261,201 Great Britain Nov. 18, 1926 

1. A NON-ACID, PHOTOGRAPHIC OXIDIZER-MODIFIER FOR ADJUSTING THE CLARITY OF, AND RETOUCHING, DEVELOPED PHOTOGRAPHS, NEGATIVE AS WELL AS POSITIVE, WHICH COMPRISES AN AQUEOUS SOLUTION OF CONCENTRATED IODINE, DECOLORIZED IODINE, AND A LOWER ALIPHATIC WATER-SOLUBLE ALDEHYDE. 